package com.qms.repast.weidgets.adsorptionhelper;

import android.annotation.SuppressLint;
import android.os.Build;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.webkit.WebView;
import android.widget.AbsListView;
import android.widget.AdapterView;
import android.widget.ScrollView;

/**
 * ================================================ 作    者：jeasonlzy（廖子尧）Github地址：https://github.com/jeasonlzy0216
 * 版    本：1.0 创建日期：2016/5/8 描    述： 修订历史： ================================================
 */
public class HeaderScrollHelper {
	//当前sdk版本，用于判断api版本
	private int sysVersion;
	private ScrollableContainer mCurrentScrollableContainer;

	public HeaderScrollHelper () {
		sysVersion = Build.VERSION.SDK_INT;
	}

	/**
	 * 包含有 ScrollView ListView RecyclerView 的组件
	 */
	public interface ScrollableContainer {

		/**
		 * @return ScrollView ListView RecyclerView 或者其他的布局的实例
		 */
		View getScrollableView ();
	}

	public void setCurrentScrollableContainer (ScrollableContainer scrollableContainer) {
		this.mCurrentScrollableContainer = scrollableContainer;
	}

	private View getScrollableView () {
		if (mCurrentScrollableContainer == null) {
			return null;
		}
		return mCurrentScrollableContainer.getScrollableView();
	}

	/**
	 * 判断是否滑动到顶部方法,ScrollAbleLayout根据此方法来做一些逻辑判断 目前只实现了AdapterView,ScrollView,RecyclerView
	 * 需要支持其他view可以自行补充实现
	 */
	public boolean isTop () {
		View scrollableView = getScrollableView();
		if (scrollableView == null) {
			throw new NullPointerException("You should call ScrollableHelper.setCurrentScrollableContainer() to set ScrollableContainer.");
		}
		if (scrollableView instanceof AdapterView) {
			return isAdapterViewTop((AdapterView) scrollableView);
		}
		if (scrollableView instanceof ScrollView) {
			return isScrollViewTop((ScrollView) scrollableView);
		}
		if (scrollableView instanceof RecyclerView) {
			return isRecyclerViewTop((RecyclerView) scrollableView);
		}
		if (scrollableView instanceof WebView) {
			return isWebViewTop((WebView) scrollableView);
		}
		throw new IllegalStateException("scrollableView must be a instance of AdapterView|ScrollView|RecyclerView");
	}

	private boolean isRecyclerViewTop (RecyclerView recyclerView) {
		if (recyclerView != null) {
			RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
			if (layoutManager instanceof LinearLayoutManager) {
				int firstVisibleItemPosition = ((LinearLayoutManager) layoutManager).findFirstVisibleItemPosition();
				View childAt = recyclerView.getChildAt(0);
				if (childAt == null || (firstVisibleItemPosition == 0 && childAt.getTop() == 0)) {
					return true;
				}
			}
		}
		return false;
	}

	private boolean isAdapterViewTop (AdapterView adapterView) {
		if (adapterView != null) {
			int firstVisiblePosition = adapterView.getFirstVisiblePosition();
			View childAt = adapterView.getChildAt(0);
			if (childAt == null || (firstVisiblePosition == 0 && childAt.getTop() == 0)) {
				return true;
			}
		}
		return false;
	}

	private boolean isScrollViewTop (ScrollView scrollView) {
		if (scrollView != null) {
			int scrollViewY = scrollView.getScrollY();
			return scrollViewY <= 0;
		}
		return false;
	}

	private boolean isWebViewTop (WebView scrollView) {
		if (scrollView != null) {
			int scrollViewY = scrollView.getScrollY();
			return scrollViewY <= 0;
		}
		return false;
	}

	/**
	 * 将特定的view按照初始条件滚动
	 *
	 * @param velocityY 初始滚动速度
	 * @param distance  需要滚动的距离
	 * @param duration  允许滚动的时间
	 */
	@SuppressLint("NewApi")
	public void smoothScrollBy (int velocityY, int distance, int duration) {
		View scrollableView = getScrollableView();
		if (scrollableView instanceof AbsListView) {
			AbsListView absListView = (AbsListView) scrollableView;
			if (sysVersion >= 21) {
				absListView.fling(velocityY);
			} else {
				absListView.smoothScrollBy(distance, duration);
			}
		} else if (scrollableView instanceof ScrollView) {
			((ScrollView) scrollableView).fling(velocityY);
		} else if (scrollableView instanceof RecyclerView) {
			((RecyclerView) scrollableView).fling(0, velocityY);
		} else if (scrollableView instanceof WebView) {
			((WebView) scrollableView).flingScroll(0, velocityY);
		}
	}
}
